Retardation of Bacterial Biofilm Formation by Coating Urinary Catheters with Metal Nanoparticle-Stabilized Polymers

Potential Application of Origanum majorana Stabilized Silver Nanoparticles for Coating of Urinary Catheter

Introduction

Urinary tract infections related to catheters are one of the most common urinary infections and can affect patient outcomes. Hence, coating urinary catheters is an important issue against several resistant bacterial pathogens that can form a resistant biofilm. This study examined the antibacterial and antibiofilm properties of the coated catheter with green silver nanoparticles (AgNPs) made from Origanum majorana.

Methods

Aloe Vera, Ocimum basilicum, Matricaria chamomilla, Foeniculum vulgare, Glycyrrhiza glabra, Origanum majorana, Urtica urens, Salvia Rosmarinus, and Salvia officinalis hydro-alcoholic extracts were prepared and tested for their antibacterial activities utilizing the agar well diffusion technique. Furthermore, O. majorana extract was tested against biofilm formation using a microtiter plate assay. UPLC-ESI-Q-TOF was used for the profiling and tentative identification of biological compounds in the O. majorana extract. O. majorana was used to prepare AgNPs-MARJ, which were characterized for their size, charge, and shape. Further, AgNPs-MARJ were used to coat two types of urinary catheters. The coated catheters were tested for their resistance to bacterial biofilm formation and compared with non-coated catheters.

Results and Discussion

Initial antimicrobial screening tests showed that O. majorana extracts presented a significant (p<0.05; ANOVA/Tukey) antibacterial activity against the studied species of bacteria compared to the other plant extracts. O. majorana extract showed MIC value of 35.0 mg/mL for E. coli, Pseudomonas aeruginosa and K. pneumoniae and displayed the highest antibiofilm activity at 100 mg/mL. LC-MS analysis tentatively identified the presence of quinic acid and flavonoid-based constituents like apigenin which contribute to the antibiofilm activity. AgNPs-MARJ were efficiently prepared with a size and charge of 111.5 nm and -19.66 mV, respectively. The coated urinary catheters showed a significant (p<0.05) decrease in Pseudomonas aeruginosa biofilm formation compared to control non-coated catheters.

Conclusion

AgNPs-MARJ offer promising prospects for addressing biofilm-related challenges in urinary tract-related catheter infections.

Spatiotemporal 3D cell impedance monitoring for metal nanoparticle risk assessment by plug-in vertical electrode array

Metal nanoparticles are commonly found in our daily lives and pose great risks to people's health. Therefore, it is crucial to establish a research model for the toxic effects of metal nanoparticles. In recent decades, three-dimensional (3D) cell models have attracted increasing interest in the fields of cell barriers, nanotoxicology, and drug screening, as they have significant advantages over two-dimensional (2D) cell models in accurately simulating in vivo behavior of human cells. The accurate spatiotemporal reaction characteristics achieved through the diffusion effect of metal nanoparticles in Matrigel scaffolds are of great importance in nanotoxicology. However, traditional impedance sensors face challenges in performing spatiotemporal dynamic impedance monitoring and evaluating the toxic impact of metal nanoparticles on 3D cells. Here, we propose an impedance sensor that integrates a plug-in vertical electrode array (PVEA) chip with a multi-channel detection system. This sensor can dynamically record 3D cell impedance in the vertical direction, which is consistent with the temporal and spatial progression of metal nanoparticle penetration, and also closely related to the spatiotemporal activity of cells influenced by metal nanoparticles. This method can detect subtle changes in impedance signals at different positions caused by the diffusion of metal nanoparticles, and has high application value in Nanotoxicology evaluation. This universal, high-throughput 3D cell impedance sensor has great potential in toxicity detection and drug screening.

Antibacterial and antifouling materials for urinary catheter coatings

Implantable medical devices have played a significant role in improving both medical care and patients' quality of life. Urinary Catheters (UCs) are commonly utilized as a substitute for bladder drainage and urine collection to prevent urinary retention in patients. However, bacterial colonization and biofilm formation on the catheter surface are prone to occur, leading to catheter-associated urinary tract infections (CAUTIs) and other complications. In recent years, UC coatings have garnered increasing attention. In this review, various antifouling and antibacterial materials for UC coatings are summarized and their impacts on bacterial activities are linked to potential mechanisms of action. Additionally, this review provides an in-depth understanding of the current advancements in UC coatings by presenting the advantages, limitations, notable achievements, and latest research findings. Finally, it anticipates the prospective design and development trajectories of UC coatings in this domain. This holds paramount significance in advancing medical device technology. STATEMENT OF SIGNIFICANCE: Combating catheter-associated urinary tract infections is a major healthcare challenge, and urinary catheter (UC) coatings are considered promising candidates to counter these infections. In this review, various antifouling and antibacterial materials for UCs are summarized, and their impacts on bacterial activities are linked to potential mechanisms of action. Additionally, the review provides an in-depth understanding of the current advancements in UC coatings by presenting the advantages, limitations, notable achievements, and latest research findings. This holds paramount significance in advancing medical device technology. This review not only contributes to the scientific research but also sparks interest among readerships and other researchers in the study of safer and more effective UC coatings for improved patient outcomes.

Current and emerging strategies to curb antibiotic-resistant urinary tract infections

Rising rates of antibiotic resistance in uropathogenic bacteria compromise patient outcomes and prolong hospital stays. Consequently, new strategies are needed to prevent and control the spread of antibiotic resistance in uropathogenic bacteria. Over the past two decades, sizeable clinical efforts and research advances have changed urinary tract infection (UTI) treatment and prevention strategies to conserve antibiotic use. The emergence of antimicrobial stewardship, policies from national societies, and the development of new antimicrobials have shaped modern UTI practices. Future UTI management practices could be driven by the evolution of antimicrobial stewardship, improved and readily available diagnostics, and an improved understanding of how the microbiome affects UTI. Forthcoming UTI treatment and prevention strategies could employ novel bactericidal compounds, combinations of new and classic antimicrobials that enhance bacterial killing, medications that prevent bacterial attachment to uroepithelial cells, repurposing drugs, and vaccines to curtail the rising rates of antibiotic resistance in uropathogenic bacteria and improve outcomes in people with UTI.

Antimicrobial and Antifungal Action of Biogenic Silver Nanoparticles in Combination with Antibiotics and Fungicides Against Opportunistic Bacteria and Yeast

The development of multidrug resistance by pathogenic bacteria and yeast is a significant medical problem that needs to be addressed. One possible answer could be the combined use of antibiotics and silver nanoparticles, which have different mechanisms of antimicrobial action. In the same way, these nanoparticles can be combined with antifungal agents. Biogenic silver nanoparticles synthesized using environmentally friendly biosynthesis technology using extracts of biologically active plants are an effective nanomaterial that needs to be comprehensively investigated for implementation into medical practice. In this study, the synergistic effects arising from their combined use with antibiotics and fungicides against various bacteria and yeasts were studied. The following methods were used: disco-diffusion analysis and construction of plankton culture growth curves. The synergistic effect of silver nanoparticles and antibiotics (fungicides) has been determined. Effective concentrations of substances were established, recommendations for the studied pathogenic species were presented, and the effect of destruction of the bacterial membrane was illustrated. The most significant synergistic effect was manifested in pathogenic candida and brewer's yeast.

Eco-friendly synthesis of silver nanoparticles by Trigonella foenum-graecum: formulations, characterizations, and application in wound healing

BACKGROUND

Due to the toxicity and serious side effects of chemical incorporated in topical dosage form used for treatment of wound healing, there is a need to use natural preparation as wound healing preparation.

AIMS

Seeds of Trigonella foenum-graecum (TFG) are used to synthesize eco-friendly silver nanoparticles (SNPs) in an appropriate way to heal wounds.

METHODS

To synthesize SNPs, TFG was incubated with AgNO3 to produce SNP-TFG. The obtained SNP-TFG was characterized for their wavelength, size and ζ-potential, surface morphology, and yield production. Then, SNP-TFG was formulated as a topical cream (O/W), characterized, and applied to the rats' groups to examine its wound-healing activity. Finally, a skin biopsy was performed to assess all rats' immunostaining and histopathological (HP) alterations in skin lesions on days 3, 7, 10, and 14.

RESULTS

The prepared SNP-TFG showed non-aggregated nano-formulation, with a λmax of 396 nm. SNP-TFG recorded a size of 43.65 ± 2.1 nm, a charge of -15.03 ± 3.2 mV, and showed yield of 52.61 ± 1.41% while the release was continued for more than 12 h. During the biosynthesis process, the compounds present in TFG are capable of reducing silver ions (Ag+) to form SNPs. SNP-TFG cream showed a pH nearly equal to the skin's pH, with suitable viscosity and homogeneity and an apparent permeability of 0.009 ± 0.001. Further, the HP of the SNP-TFG showed a substantial reduction in wound mass, wound granulation tissue growth enhancement, and epidermal re-epithelialization (proliferation) compared to the control group.

CONCLUSION

The obtained SNP-TFG is considered a novel skin wound-healing natural and eco-friendly nano-formulation.

Self-Cleaning Antibacterial Composite Coating of Fluorinated Acrylic Resin and Ag/SiO2 Nanoparticles with Quaternary Ammonium

With improvements in living standards, the demand for antibacterial self-cleaning coatings has significantly increased. In this work, self-cleaning coatings with antibacterial properties were fabricated by spray-coating a composite of fluorinated acrylic resin and Ag/SiO2 nanoparticles with quaternary ammonium salts. The synergistic action of the quaternary ammonium salts and silver nanostructures caused the coating to show a dual antibacterial effect. The Ag/SiO2 nanoparticles roughened the coating's surface and, in combination with the fluorinated chains, provided the surface a superhydrophobic self-cleaning property with a contact angle of 156° and a sliding angle of less than 2°. Notably, the composite coating withstood 100 abrasion cycles without losing its superhydrophobicity and the contact angle is still exceeded 150° after 60 h of immersion solutions with different pH values, demonstrating outstanding wear resistance and acid/alkali stability. The incorporation of nanostructured antibacterial agents was effective in improving the roughness and antibacterial properties of the low-surface-energy resin, resulting in a self-cleaning antibacterial composite coating. This method may pave a new route for the design of functional coating materials with excellent overall performance.

Can silver nanoparticles stabilized by Fenugreek (Trigonella foenm -graecum) improve tibial bone defects repair in rabbits? A preliminary study

Background

A fracture is considered a medical emergency leading to considerable complications.

Aim

This study aimed to describe the accelerating action of Ag-NPs-FG on fracture healing in rabbits.

Methods

Silver NPs (AgNPs) were reduced with fenugreek (FG), loaded into a starch gel base, and investigated for their morphology, size, and charge. Four equal groups were randomly formed of 40 adult male rabbits. A 3.5 mm diameter bone defect was created at the proximal metaphysis of the right tibia in each rabbit. Groups 1-4 were injected with placebo saline, AgNPs-FG, plain gel, and FG-gel at the bone defect zone, respectively. The healing was assessed for 8 weeks postoperatively based on the radiographic, bone turnover markers, and histopathological examinations.

Results

The AgNPs-FG was obtained as a faint reddish color, spherical in shape, with an absorbance of 423 nm, a size of 118.0 ± 1.7 nm, and a surface charge of -7.8 ± 0.518 mV. The prepared AgNPs-FG hydrogel was clear, translucent, and homogenous. The pH values were 6.55-6.5 ± 0.2, the viscosity of 4,000 and 1,875 cPs, and spreadability of 1.6 ± 0.14 and 2.0 ± 0.15 for both FG and AgNPs-FG hydrogel, respectively. The radiographic union scale was significantly (p < 0.05) improved in group 2 with a significant (p < 0.05) increase in bone turnover markers was found in comparison to other treated groups. Histopathological examination revealed the formation of mature bone on the 28th postoperative day in groups 2 and 4.

Conclusion

Colloidal nano-formulation of AgNPs-FG loaded hydrogel could be a promising formulation to accelerate rabbits' tibial bone healing process.

Urinary Catheters: Materials, Coatings, and Recommendations for Selection

Urinary catheters have been used for more than 3000 years, although materials have changed from wood to silver to rubber. Research continues to try and find the optimal catheter materials, which improve safety and quality of life. Advantages when comparing newer catheter materials are not always obvious but catheters coated with a hydrophilic layer may reduce urethral trauma and the incidence of urinary tract infections. However, extrapolation of the data is limited by lack of end-point standardization and heterogenous populations.

An Overview of Biofilm-Associated Infections and the Role of Phytochemicals and Nanomaterials in Their Control and Prevention

Biofilm formation is considered one of the primary virulence mechanisms in Gram-positive and Gram-negative pathogenic species, particularly those responsible for chronic infections and promoting bacterial survival within the host. In recent years, there has been a growing interest in discovering new compounds capable of inhibiting biofilm formation. This is considered a promising antivirulence strategy that could potentially overcome antibiotic resistance issues. Effective antibiofilm agents should possess distinctive properties. They should be structurally unique, enable easy entry into cells, influence quorum sensing signaling, and synergize with other antibacterial agents. Many of these properties are found in both natural systems that are isolated from plants and in synthetic systems like nanoparticles and nanocomposites. In this review, we discuss the clinical nature of biofilm-associated infections and some of the mechanisms associated with their antibiotic tolerance. We focus on the advantages and efficacy of various natural and synthetic compounds as a new therapeutic approach to control bacterial biofilms and address multidrug resistance in bacteria.

Synthesis and characterization of magnetic Ag-Fe3O4@polymer hybrid nanocomposite systems with promising antibacterial application

INTRODUCTION

Bacterial infections caused by different strains of bacteria still one of the most important disorders affecting humans worldwide. Polymers nanocomposite systems could be considered as an alternative to conventional antibiotics to eradicate bacterial infections.

SIGNIFICANCE

In an attempt to enhance the antibacterial performance of silver and iron oxide nanoparticles, decrease their aggregation and toxicity, a polymeric hybrid nanocomposite system combining both nanoparticles is produced.

METHODS

Magnetic Ag-Fe3O4@polymer hybrid nanocomposites prepared using different polymers, namely polyethylene glycol 4000, ethyl cellulose, and chitosan were synthesized via wet impregnation and ball-milling techniques. The produced nanocomposites were tested for their physical properties and antibacterial activities.

RESULTS

XRD, FT-IR, VSM, and TEM results confirmed the successful preparation of hybrid nanocomposites. Hybrid nanocomposites have average crystallite sizes in the following order Ag-Fe3O4@CS (8.9 nm) < Ag-Fe3O4@EC (9.0 nm) < Ag-Fe3O4@PEG4000 (9.4 nm) and active surface area of this trend Ag-Fe3O4@CS (130.4 m2g-1) > Ag-Fe3O4@EC (128.9 m2g-1) > Ag-Fe3O4@PEG4000 (123.4 m2g-1). In addition, they have a saturation magnetization in this order: Ag-Fe3O4@PEG4000 (44.82 emu/g) > Ag-Fe3O4@EC (40.14 emu/g) > Ag-Fe3O4@CS (22.90 emu/g). Hybrid nanocomposites have a pronounced antibacterial action against Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus intermedius compared to iron oxide nanoparticles and positive antibacterial drug. In addition, both Ag-Fe3O4@EC and Ag-Fe3O4@CS have a lower MIC values compared to Ag-Fe3O4@PEG and positive control.

CONCLUSION

Magnetic Ag-Fe3O4 hybrid nanocomposites could be promising antibacterial nanomaterials and could pave the way for the development of new materials with even more unique properties and applications.

All-in-one properties of an anticancer-covered airway stent for the prevention of malignant central airway obstruction

Malignant central airway obstruction (MCAO) resulting from tumor metastasis and compression severely impairs respiration, posing life-threatening risks. To address this, we employed a synergistic modification strategy, combining cisplatin (CIS) and silver nanoparticles (AgNPs). Polycaprolactone (PCL) served as a drug carrier, enabling the preparation of a functional CIS@AgNPs@PCL fiber membrane-covered airway stent via electrospinning. This approach aimed to enhance the patency rate of MCAO. Characterization via ATR-FTIR, scanning electron microscope-energy-dispersive spectroscopy, and transmission electron microscope confirmed successful immobilization of CIS and AgNPs onto the stent surface. CIS@AgNPs@PCL substantially suppressed non-small cell lung cancer cells (A549), causing DNA damage, ultrastructural disruption, and over 50% apoptosis in 48 h. It also displayed potent antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans biofilms. A mouse subcutaneous tumor recurrence model assessed anti-cancer efficacy. CIS@AgNPs@PCL fiber-covered stents significantly inhibited lung cancer tissue and enhanced anti-cancer effects by up-regulating caspase-3 and Bax, while down-regulating Bcl-2. This study's functional airway stent provides a proof-of-concept for an integrated anti-cancer and antibacterial strategy. It promptly restores the lumen, inhibits biofilm formation, prevents tumor progression, and improves postoperative MCAO patency.

Advances in Nanotechnology for Biofilm Inhibition

Biofilm-associated infections have emerged as a significant public health challenge due to their persistent nature and increased resistance to conventional treatment methods. The indiscriminate usage of antibiotics has made us susceptible to a range of multidrug-resistant pathogens. These pathogens show reduced susceptibility to antibiotics and increased intracellular survival. However, current methods for treating biofilms, such as smart materials and targeted drug delivery systems, have not been found effective in preventing biofilm formation. To address this challenge, nanotechnology has provided innovative solutions for preventing and treating biofilm formation by clinically relevant pathogens. Recent advances in nanotechnological strategies, including metallic nanoparticles, functionalized metallic nanoparticles, dendrimers, polymeric nanoparticles, cyclodextrin-based delivery, solid lipid nanoparticles, polymer drug conjugates, and liposomes, may provide valuable technological solutions against infectious diseases. Therefore, it is imperative to conduct a comprehensive review to summarize the recent advancements and limitations of advanced nanotechnologies. The present Review encompasses a summary of infectious agents, the mechanisms that lead to biofilm formation, and the impact of pathogens on human health. In a nutshell, this Review offers a comprehensive survey of the advanced nanotechnological solutions for managing infections. A detailed presentation has been made as to how these strategies may improve biofilm control and prevent infections. The key objective of this Review is to summarize the mechanisms, applications, and prospects of advanced nanotechnologies to provide a better understanding of their impact on biofilm formation by clinically relevant pathogens.

Self-Disinfecting Urethral Catheter to Overcome Urinary Infections: From Antimicrobial Photodynamic Action to Antibacterial Biochemical Entities

Medical-device-related infections are considered a worldwide public health problem. In particular, urinary catheters are responsible for 75% of cases of hospital urinary infections (a mortality rate of 2.3%) and present a high cost for public and private health systems. Some actions have been performed and described aiming to avoid it, including clinical guidelines for catheterization procedure, antibiotic prophylaxis, and use of antimicrobial coated-urinary catheters. In this review paper, we present and discuss the functionalization of urinary catheters surfaces with antimicrobial entities (e.g., photosensitizers, antibiotics, polymers, silver salts, oxides, bacteriophage, and enzymes) highlighting the immobilization of photosensitizing molecules for antimicrobial photodynamic applications. Moreover, the characterization techniques and (photo)antimicrobial effects of the coated-urinary catheters are described and discussed. We highlight the most significant examples in the last decade (2011-2021) concerning the antimicrobial coated-urinary catheter and their potential use, limitations, and future perspectives.

Optimized Green Synthesis and Anticancer Potential of Silver Nanoparticles Using Juniperus procera Extract Against Lung Cancer Cells

Silver nanoparticles (AgNPs) have been considered promising candidates for medical practices in various fields. This study proposed an efficient, economical, uncomplicated, and reliable method to synthesize AgNPs utilizing leaf and fruit extracts of Juniperus procera (J. procera) as capping, reducing, and stabilizing agents. The study includes optimizing the green synthesis conditions to produce stable AgNPs with high yields, acceptable particle size, and shape, hence, AgNPs may be used for different medical purposes through the improvement of their properties. Several spectroscopic and other analyses performed characterization of the fabricated AgNPs, and the results show stable and spherical AgNPs between 14 and 18 nm in size. The study also evaluated the anticancer activities of the biosynthesized AgNPs using J. procera fruit and leaf extracts against in vitro lung cancer A549 and H1975 cells. The results demonstrate the high toxicity of the biosynthesized AgNPs against in vitro lung cancer cells, supporting therapeutic and biomedical applications of AgNPs.

A Metal-Containing NP Approach to Treat Methicillin-Resistant Staphylococcus aureus (MRSA): Prospects and Challenges

Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of pneumonia in humans, and it is associated with high morbidity and mortality rates, especially in immunocompromised patients. Its high rate of multidrug resistance led to an exploration of novel antimicrobials. Metal nanoparticles have shown potent antibacterial activity, thus instigating their application in MRSA. This review summarizes current insights of Metal-Containing NPs in treating MRSA. This review also provides an in-depth appraisal of opportunities and challenges in utilizing metal-NPs to treat MRSA.